Australians, and no doubt a few New Zealand tourists, are getting ready to bring in 2019 in a pool of sweat.

Forecasters say the heatwave most Aussies have been struggling with is due to stick around for at least another week.

Sky News chief meteorologist Tom Saunders told news.com.au most parts of the country can expect a traditional Aussie New Year's Eve with hot, sticky conditions forecast for Sydney, Melbourne, Brisbane, Perth, Canberra and Adelaide.

Hobart will also see a relatively normal New Year's Eve with temperatures forecast in the high 20s while Darwin, in the middle of its wet season, will experience a hot and humid night with potential for thunderstorms.

New Year's Day is also forecast to be hot, dry and sunny across much of the country.

Despite the sunny forecast for Australia's capitals, other parts of the country are dealing with catastrophic heatwaves, possible floods, fires and cyclones.

Much of southern Australia has also spent the end of the year experiencing temperatures 10-14C higher than usual for this time.

"The whole country is stuck in what's called a blocking pattern, which is a stagnant weather pattern where most places are seeing the same weather every day," Saunders said.

"The blocking high pressure system is sitting in the Tasman Sea, and it's been there since [last] Monday and is forecast to stay at least another week.

"It's not really changing and it's not moving which means that heatwave is going to stick around until at least mid-next week."

QUEENSLAND

Queenslanders could soon be bracing for the first cyclone of the season, as a monsoon trough develops over the north of the continent. Saunders said there was potential for a cyclone in Far North Queensland, with the same region warned to expected heavy rain. There are flood warnings for the Daintree River and flood watches for the Mossman, Mulgrave and Russell rivers. Saunders said other parts of Queensland, including Brisbane and the Gold Coast, were experiencing temperatures only a couple of degrees hotter than normal. In Brisbane, the mercury is tipped to hit 31C.

VICTORIA

Melbourne had been sweltering but relief finally came at the weekend when the Victorian capital was hit with a cool change. Melburnians, who were struggling through 35C-plus days from before Christmas saw a drop of 10C to 25C on Saturday. "The cool change is close to the NSW border so parts of NSW will feel that release also," Saunders said. Other parts of the state are still sweltering. Hot, dry conditions mean severe fire danger warnings are in place for the Mallee, Wimmera and northern country districts, including Mildura, Swan Hill, Kerang and Echuca where the temperature could reach 44C.

NEW SOUTH WALES

The millions of people headed to Sydney's world-famous fireworks are in for a sweaty night with the lengthy December heatwave showing no signs of letting up. "New Year's Day will be day nine of that heatwave," Saunders said. There was no significant rain forecast for NSW and Sydney but there was potential for afternoon and evening thunderstorms.

SOUTH AUSTRALIA

Dozens of December heat records were toppled leading up to New Year's. Catastrophic fire danger kept residents on high alert but the southern parts of the state, including Adelaide, finally experienced a cool change late on Friday. Adelaide had its hottest December day since 1931 on December 27 with the mercury hitting 43.7C. Leaving 2018, Adelaide can expect sunny skies and highs of 30C today with similar 30C-plus temperatures forecast for tomorrow.

WESTERN AUSTRALIA

It'll be sunny skies for Perth too with Saunders noting the southern part of Western Australia wasn't "going to see much happening at all" on the weather front. Today and tomorrow will see the mercury hit the high 20s and low 30s. But the north will be extremely hot with most of the region forecast to hit the mid-40s.

TASMANIA

Hobart, alongwith the rest of Tasmania, will say hello to 2019 with average summer weather. Hobart is forecast to hit 25C.

NORTHERN TERRITORY

In the middle of its wet season, the Northern Territory is forecast to be lashed with rain and thunderstorms. Darwin can expect highs of 33C.